oWell my toons at lvl 19 (tank is 21), I went for 3 mages, priest and a pally.
My priest spends most of his time doing nothing and only healing on big fights I have not mastered casting different heal spells I just use the big heal which is good when its only my tank taking damage but when they all start getting hit its harder. Need to learn to get better at casting hots.

I can control my mages or my pally well but I have not really mastered both at the same time yet. ATM I have no overlap with my mages and pally comands I control my pally total by mouse and mages by keyboard with a follow + assist pally button.
I've tried Deadmines 2 times the second time I nearly got to the end boss before getting red gear. My pally was only added to the group when I got to level 18 so I'm just getting the hang of playing 3 classes.

Thanks for all your input.